The present invention relates to ignition systems for internal combustion engines, and particularly high power, high energy distributorless capacitive discharge ignition systems for multi cylinder engines. Such ignition is essential to the operation of high efficiency internal combustion engines using the more difficult to ignite dilute mixtures, such as lean mixtures, high residual or high EGR mixtures, and fuel-air mixtures of the more difficult to ignite fuels such as alcohol fuels, natural gas, and others. Such high power, high energy ignition delivers power to the mixture at the rate of hundreds of watts versus tens of watts for conventional inductive ignition and conventional high energy ignition. Total useful energy delivery to the mixture ranges from about fifty millijoules to several hundred millijoules, versus five to twenty millijoules for conventional high energy ignition.
The distributorless feature of the ignition is achieved by the use of a separate leakage inductor disclosed in the prior and copending U.S. patent application Ser. No. 7-350,945, and the high power/high energy feature by the use of the voltage doubling principle disclosed in U.S. Pat. No. 4,677,960 and its improvements. The ignition control system is based in part on U.S. Pat. No. 4,688,538. U.S. Pat. Nos. 4,774,914, 4,841,925, and 4,868,730 are also relevant to other features presented herein including improved power converter and energy recharge circuit, SCR speed-up turn-off circuit, and others. Also, plasma jet type ignition of U.S. Pat. No. 4,317,068 is referenced since it is improved by features disclosed herein. The said application and all said patents are of common assignment with this application and the text and drawings of said prior application and patents are incorporated herein by reference as though set out at length herein.
Reference to the above cited application and patents is sometimes made herein as '945 application, and '960, '538, '914, '925, '730, and/or '068 patent(s), respectively.